Deviation from ideal behaviour and compressibility factor

44 questions on Deviation from ideal behaviour and compressibility factor from the Real Gases chapter: 8 NEET level, 16 JEE Main, 20 JEE Advanced. Each one opens with its answer and solution.

• The compressibility factor Z of a gas is defined as Z = (PV)/(nRT). For an ideal gas at all pressures and temperatures, Z is NEET level
• At very low pressure (well below 1 atm) and moderate temperature, the compressibility factor of CO2 is slightly less than 1. The main reason is NEET level
• A fixed amount of a real gas is compressed isothermally at a temperature below its Boyle temperature. Which statements about the compressibility factor Z are co... JEE Advanced level
• One mole of a real gas occupies 0.40 L at 50 atm and 300 K. Taking R = 0.0821 L atm K^-1 mol^-1, the compressibility factor Z of the gas (two decimals) is JEE Main level
• At a certain pressure and temperature a real gas has compressibility factor Z = 1.35. If an ideal gas under identical conditions and amount would occupy 10.0 L,... JEE Main level
• Which of the following correctly orders the gases by the depth of the minimum in their Z versus P curves at 273 K (deepest minimum first)? JEE Main level
• A gas of molar mass M has density rho at pressure P and temperature T. Its compressibility factor is given by JEE Main level
• At 20 atm and 400 K the compressibility factor of CO2 (molar mass 44 g mol^-1) is 0.92. Using R = 0.0821 L atm K^-1 mol^-1, the density of the gas in g L^-1 (tw... JEE Main level
• Consider the plot of Z against P for a real gas at a fixed temperature T that is below its Boyle temperature. Which statements are correct? JEE Advanced level
• A cylinder of volume 2.0 L contains nitrogen at 100 atm and 300 K, where Z = 1.25. The mass of nitrogen in the cylinder, in grams (one decimal), is (molar mass ... JEE Advanced level
• At 300 K and the same moderate pressure, the compressibility factor of He is slightly greater than 1 while that of NH3 is well below 1. The best explanation is JEE Advanced level
• Real gases deviate most from ideal behaviour under the conditions of NEET level
• A gas shows Z = 0.85 at a certain pressure and temperature. This means that the gas is NEET level
• At 300 K and 50 atm, which of the following gases is expected to have the compressibility factor closest to 1? JEE Main level
• At 300 K and 60 atm, 1 mol of a gas occupies 0.328 L. Taking R = 0.0821 L atm K^-1 mol^-1, the compressibility factor is closest to JEE Main level
• Two moles of a gas at 500 K and 80 atm have Z = 1.15. Using R = 0.0821 L atm K^-1 mol^-1, the volume of the gas in litres (two decimals) is JEE Main level
• A gas has density 12.60 g L^-1 at 10.0 atm and 300 K, where its compressibility factor is 0.95. Using R = 0.0821 L atm K^-1 mol^-1, its molar mass in g mol^-1 (... JEE Main level
• The Z versus P curves of a gas are drawn at three temperatures T_1, T_2 and T_3. At T_1 the curve has a deep minimum, at T_2 a shallow minimum and at T_3 it ris... JEE Advanced level
• One mole of O2 (a = 1.36 L^2 atm mol^-2, b = 0.0318 L mol^-1) is held at 400 K in a volume of 0.300 L. Using the van der Waals equation, the compressibility fac... JEE Advanced level
• One mole of CO2 (a = 3.59 L^2 atm mol^-2, b = 0.0427 L mol^-1) occupies 0.200 L at 300 K. Using the van der Waals equation and R = 0.0821 L atm K^-1 mol^-1, the... JEE Advanced level
• Which of the following statements regarding compressibility factor are correct? JEE Advanced level
• The compressibility factor of a gas can be written to first order as Z = 1 + (P)/(RT)(b - (a)/(RT)). For nitrogen (a = 1.39 L^2 atm mol^-2, b = 0.0391 L mol^-1,... JEE Advanced level
• Which two assumptions of the kinetic theory of gases fail for real gases at high pressure? NEET level
• A plot of PV against P for one mole of a real gas at constant temperature is JEE Main level
• Assertion (A): The compressibility factor of a real gas is less than 1 at moderate pressures and low temperature. Reason (R): At these conditions the attractive... NEET level
• One mole of a gas at 300 K and 5.0 x 10^6 Pa occupies 4.0 x 10^-4 m^3. Taking R = 8.314 J K^-1 mol^-1, the compressibility factor (two decimals) is JEE Main level
• The compressibility factor of a gas at a given temperature falls from 1 to a minimum of 0.80 as pressure increases, then rises. The pressure at which Z = 1 agai... JEE Advanced level
• At 320 K and 25 atm the compressibility factor of a gas is 0.88 (R = 0.0821 L atm K^-1 mol^-1). Which statements are correct? JEE Advanced level
• Match the following gases with the shape of their Z versus P curve at 273 K. Gases: (P) H2, (Q) CO2. Curves: (1) Z rises continuously above 1 from the start; (2... JEE Main level
• For ammonia a = 4.17 L^2 atm mol^-2 and b = 0.0371 L mol^-1. Using the low-pressure approximation Z = 1 + (P)/(RT)(b - (a)/(RT)) with R = 0.0821 L atm K^-1 mol^... JEE Advanced level
• At 273 K a gas has Z = 1.0010 at 1 atm and Z = 0.9990 at a different pressure P_2, both in the low-pressure region where Z is linear in P. Which statement is ne... JEE Advanced level
• A real gas is described by Z = 1 + (P)/(RT)(b - (a)/(RT)) at low pressure. Which statements follow from this expression? JEE Advanced level
• The molar volume of a real gas at 300 K and 20 atm is measured as 1.15 L mol^-1 (R = 0.0821 L atm K^-1 mol^-1). Which statements are correct? JEE Advanced level
• The compressibility factor of a gas is found to be exactly 1 at a particular pressure and temperature. Which conclusion is correct? NEET level
• For a real gas at the same T and P as an ideal gas, Z = 0.5 means that JEE Main level
• Which graph correctly represents the behaviour of an ideal gas on a plot of Z versus P? NEET level
• A sample of gas occupies 5.40 L at a state where its compressibility factor is 1.08. The volume that the same amount of an ideal gas would occupy at the same P ... JEE Main level
• The compressibility factor of N2 at 300 K is 0.9985 at 1 atm, 0.98 at 20 atm and 1.06 at 200 atm (approximate values). Which statement is correct? JEE Main level
• 0.500 mol of a gas with compressibility factor 0.92 is held in 1.20 L at 320 K (R = 0.0821 L atm K^-1 mol^-1). The pressure in atm (two decimals) is JEE Main level
• Assertion (A): At 273 K the Z versus P curve for H2 lies entirely above Z = 1. Reason (R): For H2 at 273 K the term a/RT is smaller than b. Choose the correct o... JEE Advanced level
• Nitrogen (molar mass 28 g mol^-1) has density 12.80 g L^-1 at 10.0 atm and 300 K. Taking R = 0.0821 L atm K^-1 mol^-1, its compressibility factor (three decimal... JEE Advanced level
• At 0 degC the Z versus P curves of CH4 and N2 both show minima. Given a(CH4) = 2.25, a(N2) = 1.39 (in L^2 atm mol^-2) and b nearly equal, which statement is cor... JEE Advanced level
• The compressibility factor Z of a gas is 0.9800 at 10.0 atm and 300 K and the dependence is linear in P in this region (R = 0.0821 L atm K^-1 mol^-1). Which sta... JEE Advanced level
• Which of the following statements about real gases are correct? JEE Advanced level